We propose to continue to train students in the molecular biology of signal transduction-the mechanisms by which extracellular hydrophilic hormones, growth factors and neurotransmitter generate intracellular responses that are important in differentiation, proliferation and other cellular processes. We use Dictyostelium as a model system and have identified genes that respond to stimulation of cell surface receptors by extracellular cAMP interacting with cell surface receptors. Regulatory sites on one gene have been characterized and proteins that interact with them have been purified. Reversible protein phosphorylation has been implicated in the process. The parent project is supported by an NIH R01 grant until 1995. The MBRS student will assist in the isolation of clones encoding phosphoprotein phosphatases or protein kinases and the disruption of the genes. These studies will help to elucidate the roles of specific kinases in the signal transduction pathways. The active participation by MBRS students will help them to understand research techniques and to learn to function as scientists in the future.